CN1061162C - Hot-pressed magnets formed from anisotropic powders - Google Patents
Hot-pressed magnets formed from anisotropic powders Download PDFInfo
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- CN1061162C CN1061162C CN93120694A CN93120694A CN1061162C CN 1061162 C CN1061162 C CN 1061162C CN 93120694 A CN93120694 A CN 93120694A CN 93120694 A CN93120694 A CN 93120694A CN 1061162 C CN1061162 C CN 1061162C
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
- H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
- H01F1/047—Alloys characterised by their composition
- H01F1/053—Alloys characterised by their composition containing rare earth metals
- H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
- H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
- H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
- H01F1/0575—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together
- H01F1/0576—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together pressed, e.g. hot working
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- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
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- B22F3/14—Both compacting and sintering simultaneously
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Abstract
A method is provided for forming a high energy product, anisotropic, hot pressed iron-rareoboron metal permanent magnet without the requirement for magnetic alignment during pressing or additional hot working steps. The method of this invention includes providing a quantity of anisotropic iron-rare-boron metal particles and hot pressing the particles so as to form a substantially anisotropic permanent magnet. The pressed permanent magnet of this invention permits a greater variety of shapes as compared to conventional hot worked anisotropic permanent magnets. As a result, the magnetic properties and shape of the permanent magnet of this invention can be tailored to meet the particular needs of a given application.
Description
In a broad aspect, the present invention relates to mainly with iron, neodymium and/or praseodymium and boron are the high energy product permanent magnet preparation method on basis.More particularly, the present invention relates to form the method for hot pressing rare-earth-iron-boron permanent magnet, wherein alloy is carried out hot pressing and hot working step, thereby make hot working body with sheet-like crystallite microscopic structure with the rare-earth-iron-boron alloy.
Containing iron, the composition of neodymium and/or praseodymium and boron is the known and commercial Application of the permanent magnet on basis.Contain cubic crystal grain mutually as basic magnetic in these permanent magnets, iron wherein, the ratio of neodymium and boron etc. can be with for example empirical formula Nd
2Fe
14B represents.These magnet compositions and manufacture method thereof have seen the United States Patent (USP) (US) 4802931 (promulgation on February 7th, 1989) of Croat.Surround second phase around the magnetic phase crystal grain, compare with basic magnetic, this is rich in rare earth mutually usually as being rich in neodymium.The known magnet that forms based on these compositions can solidify rapidly as the banded sheet of the crystallite of making magnetic isotropy by fast melt-quenching by making the said composition melt.Available these isotropism particles form magnet by well-known method, as particle and appropriate resin are bonded together.
Though the magnet with these isotropic strap moulding is gratifying for some application, but its magnetic energy product (BHmax) is about 63643.5AT/m usually to about 79554.4AT/m (about 10 mega gaussorersteds of about 8-(MGOe)), and this is not enough for many other purposes.In order to improve magnetic energy product, the known magnet that the isotropism particle can be hot pressed into the about 103420.7AT/m of magnetic energy product to about 171376.2AT/m (the about 14MGOe of about 13-).US4782367 (promulgation on December 20th, 1988) points out, suitably hot pressing and the hot working and make its plastic deformation of the anisotropic powder of fast melt-quenching, thus obtain high-intensity magnetic anisotropy permanent magnet.Owing to be magnetic anisotropy, these magnets demonstrate extremely excellent magnetism, and its magnetic energy product is generally about 222752.3AT/m (about 28MGOe) or higher.But, the shortcoming of the anisotropy magnet of moulding is like this, because the final molding step is plastic deformation process, thus the shape that anisotropy magnet can moulding obviously be restricted, especially like this by comparison with the different shape that bonding hot pressing isotropic magnet can reach.
Another shortcoming in the rare-earth-iron-boron anisotropy magnet production technology is that required several procedure of processings are time-consuming, and the hot working step that increases has also strengthened the production cost of these magnets.In addition, magnet hot working is die needed and drift is generally very complicated, makes it be difficult to make and use.Therefore, rare-earth-iron-boron anisotropy permanent magnet production cost is very high usually, and its shape is subjected to the restriction of former.
The known magnet that is made of the bonding anisotropic particle, the about 119331.6AT/m of its magnetic energy product is to about 143197.9AT/m (the about 18MGOe of about 15-).Adopt known method, as mechanical milling method, pulverizing and hydrogen decrepitation method can be made anisotropic particle with aforesaid hot working anisotropy magnet.Then anisotropic particle is bonded together with suitable adhesive, thereby make permanent magnet, wherein adhesive can be used for example thermosetting resin or thermoplastic resin.But, in order to reach these high energy product values, must in the course of processing, be placed on particle in the alignment magnetic field or, the described such particle of orientation in advance that adopts of 438 (promulgations on June 25th, 1991) as U.S. Patent No. 5,026.The permanent magnet shape that therefore, can obtain is still very limited.In addition, following process is also more difficult, and complex process, because these particles magnetize, this is harmful especially in computer industry, the operation of spuious magnetic-particle meeting grievous injury memory in computer industry.
Thus, though above-mentioned existing permanent magnet is suitable for many purposes, but still need provide magnetic energy product to be at least 119331.6AT/m (15MGOe) and higher, about better 159108.8AT/m (about 20MGOe) or higher permanent magnet formation method, wherein the advantage of this method is can make permanent magnet and this method with wide variety of shapes both not required the hot working step, does not also require and carry out magnetic field orientating in hot pressing.
Hot pressing rare-earth-iron-boron magnet manufacture method of the present invention is characterised in that this method is further comprising the steps of: with the fragmentation of said hot working body to make a certain amount of magnetic anisotropy rare-earth-iron-boron alloying pellet with it with laminated structure; Then will this quantitative magnetic anisotropy rare-earth-iron-boron alloying pellet hot pressing make magnetic long-pending is the hot pressing magnetic anisotropy rare-earth-iron-boron alloy permanent magnet of 119331.6AT/m (15MGOe) together at least, this heat-press step can be carried out under the state of no alignment magnetic field, and this can not influence the magnetic anisotropy and the magnetic energy product of magnetic anisotropy hot pressing rare-earth-iron-boron alloy permanent magnet basically simultaneously; Described hot pressing rare-earth-iron-boron alloy permanent magnet has the structure that is formed by flaky crystalline grain and demonstrates magnetic anisotropy, and its magnetic energy product is higher than the magnetic energy product of the hot pressing magnetic isotropy magnet with similar composition, is lower than the magnetic energy product of said hot working body.
Therefore, the purpose of this invention is to provide a kind of anisotropy hot pressing permanent magnet, its magnetic energy product is 119331.6AT/m (15MGOe) at least, is 159108.8AT/m (29MGOe) better at least, need not magnetic field orientating in the hot pressing anisotropic particle is made the process of magnet.
Another purpose of the present invention is the anisotropic basically permanent magnet that this method can form shape of all kinds, the shape style that its shape style may reach more than the anisotropy permanent magnet made from common hot-working method.
Another purpose of the present invention is that magnetic components should be mainly with neodymium and/or praseodymium during this anisotropy hot pressing set of permanent magnets became, and iron and boron be basic cubic crystalline phase RE
2TM
14B.
Another purpose of the present invention is that this permanent magnet should contain the magnetic anisotropy particle, and might add the magnetic isotropy particle, and wherein the relative quantity of each particle can be determined the magnetic of permanent magnet.
Another purpose of the present invention is that this permanent magnet forming method should be that the hot pressing of a certain amount of magnetic anisotropy particle is made together is anisotropic permanent magnet basically, or on the other hand a certain amount of anisotropy and the hot pressing of isotropism particle are made together to small part be anisotropic permanent magnetism.
According to the preferred embodiments of the invention, above-mentioned and other purpose and advantage are summarized as follows.
According to the present invention, a kind of manufacture method of anisotropy hot pressing rare-earth-iron-boron permanent magnet is provided, wherein the permanent magnet magnetic energy product is 119331.6AT/m (15MGOe) at least, is 159108.8AT/m (20MGOe) better at least.And, magnetic energy product of the present invention can be in the anisotropic particle hot pressing without magnetic field orientating and can anisotropic particle not carried out hot working and obtain.
The inventive method comprises provides a certain amount of anisotropy rare-earth-iron-boron particle, and can add isotropism rare-earth-iron-boron particle, and it is anisotropic high energy product permanent magnetism basically that these particles are hot pressed into.As anisotropic hot pressing permanent magnet, the shape quantity that its shape quantity obtains more than hot worked anisotropy permanent magnet far away.In addition, owing in hot pressing, need not the conventional magnetic field orientating operation that requires can obtain the high energy product magnet, so this method is easy to obtain the magnet shape of various complexity.The magnetic property of permanent magnet of the present invention and shape can follow-up adjustment to satisfy the specific requirement of determining purposes.
In general, magnet of the present invention is formed the mixture that comprises about 40-90% iron or cobalt and iron (TM) in atomic percent, and about 10-40% rare earth metal (RE) must comprise neodymium and/or praseodymium in this rare earth metal, and at least 0.5% boron.Preferably, iron accounts at least 40 atom % of total composition, and neodymium and/or praseodymium account at least 6 atom % of total composition.And preferably, boron content is total about 0.5-10 atom % that forms, but total boron content requires suitably to be higher than this scope according to purposes.Further preferably iron should account at least 60 atom % of non-rare earth metal content, and neodymium and/or praseodymium should account at least 60 atom % of rare earth metal content.Though be to provide in the described specific embodiment of the invention in back with the percentage by weight that falls into above-mentioned atom % scope, should be noted that iron, rare earth, the composition of boron and each composition of cobalt can great changes will take place in above-mentioned preferred atomic ratio scope.
Also can there be a small amount of other metal, both independent metal, the also metal of combination, its amount is about 1 weight % (Wt%) at most.These metals comprise tungsten, chromium, nickel, aluminium, copper, magnesium, manganese, gallium, niobium, vanadium, molybdenum, titanium, tantalum, zirconium, carbon, tin and calcium.The same as a small amount of oxygen of normal existence with nitrogen, also there is minor amount of silicon usually.
Adopt known method promptly to can be made into the isotropism particle as the suitable rare-earth-iron-boron composition of fast melt-quenching under the optimal conditions of excessive chilling.Contain about 26-32% rare earth by weight percentage in preferred the composition, about 2-16% cobalt, about 0.7-1.1% boron, all the other are essentially iron.The particle that this technology is made is generally band shape and is easy to narrow down to and requires particle size.
Anisotropic particle is preferably made by known method of the prior art, wherein will have the hot pressing of isotropism particle and the hot working of above-mentioned preferred composition, so that isotropic each particle generation plastic deformation, thereby make the sheet anisotropic particle.The anisotropic thermal processome that obtains is like this pressed known method such as mechanical milling method then, and comminuting method or hydrogen decrepitation method are broken and make a certain amount of anisotropic particle.Applicable hot working shape can be simple geometric shape such as the rectangular block that is easy to by the heat processing technique moulding, cylinder etc.The dimensional accuracy and the surface smoothness of this hot working body are not critical to the invention, and will be broken into particle because this hot working body is follow-up.Unique needs be high energy product hot working magnet, need not any specific shape or the precision of size.
Definite by the present invention, can be made into permanent magnet by hot pressing certain amount of plastic deformation magnetic anisotropy particle, its magnetic energy product is 19331.6AT/m (15MGOe) at least, is at least 159108.8AT/m (20MGOe) better, and need not use magnetic field in hot pressing.On the other hand, hot pressing isotropism and anisotropic granulate mixture also can be made into permanent magnet, and its magnetic energy product is about 19331.6AT/m to 167064.2AT/m (15-21MGOe), need not use any magnetic field equally in hot pressing.
By the present invention's first preferred embodiment, the a certain amount of anisotropic particle of hot pressing itself can be made into anisotropic basically permanent magnet, its magnetic is better than existing bonding and hot pressing isotropic magnet and existing bonding anisotropy magnet, and just more strong with the contrast of common anisotropy hot working magnet magnetic.In addition, the shape quantity that anisotropy permanent magnet of the present invention can be made is far away more than can obtainable shape quantity with conventional hot working anisotropy magnet, and the hot working as last procedure of processing under latter event has seriously limited the shape quantity that available permanent magnet obtains.
Therefore, favorable characteristics of the present invention is easily to reach 119331.6AT/m (15MGOe) at least in the magnet that said method is made, be at least the magnetic energy product of 159108.8AT/m (20MGOe) better, and need in hot pressing or its other hot procedure, carry out magnetic field orientating before not resembling the magnet particle.
In addition, as previously mentioned, another obvious advantage of the present invention is that the final geometry of anisotropy hot pressing permanent magnet of the present invention is determined by hot press operation.Therefore, permanent magnet of the present invention can obtainable shape quantity can obtainable shape quantity more than existing hot working anisotropy magnet, can reach again simultaneously can be by comparison magnetic energy product.
From following detailed description and accompanying drawing, can clearly be seen that other purpose of the present invention and advantage.
Fig. 1 shows by the demagnetization curve of the preferred embodiment of the invention with the granuloplastic hot-pressed magnets of magnetic anisotropy of preferred iron-neodymium-boron composition.
Fig. 2 shows each the demagnetization curve of hot-pressed magnets of the magnetic anisotropy shaping particles of forming along the preferred iron-neodymium of usefulness shown in Figure 1-boron.
The preferred process of the present invention is produced rare-earth-iron-boron high energy product anisotropy compacting permanent magnet, wherein need not carry out magnetic aligning in its particle pressing process or in other hot procedure and just can reach high energy product.Method for optimizing comprises the isotropism rare-earth-iron-boron particle that may add and a certain amount of anisotropy rare-earth-iron-boron particle hot pressing and makes high energy product anisotropy permanent magnet.
The suitable composition of iron-rare-earth metal permanent magnet of the present invention comprises suitable transition metal (TM) component, suitable rare earth (RE) component and boron (B) and little cobalt, and available empirical formula RE
2TM
14B represents.As previously mentioned, the preferred mixture that comprises about 40-90% iron or iron and cobalt in atomic percent of forming, wherein iron preferably accounts at least 60% of non-rare earth metal content; About 10-40% rare earth metal wherein must comprise neodymium and/or praseodymium, and neodymium and/or praseodymium preferably account at least 60% of content of rare earth; And at least 0.5% boron.Preferably, iron accounts at least 40 atom % of total composition, and neodymium and/or praseodymium account at least 6 atom % of total composition.The boron content range is preferably about 0.5-10 atom % of total composition, but according to the purposes that requires of magnetic composition, total boron content can suitably be higher than this scope.Also can have a small amount of other metal, its amount is about 1Wt% at most, available other metal single or combination, and these metal examples can be enumerated tungsten, chromium, nickel, aluminium, copper, magnesium, manganese, gallium, niobium, vanadium, molybdenum, titanium, tantalum, zirconium, carbon, tin and calcium.Usually also can there be minor amount of silicon, oxygen and nitrogen.Should be used for effective permanent magnet composition of the present invention is described at US 4802931.
Be used to make this hot working anisotropy permanent magnet and contained by Fe
14Nd
2The specific composition of the magnetic phase that B (or equivalent) tetragonal crystal is formed is expressed as follows with corresponding percentage by weight: about 26-32% rare earth (wherein this composition at least about 95% being neodymium, and all the other are essentially praseodymium); About 0.7-1.1% boron; All the other are iron, wherein replace iron with cobalt in some cases, and its ratio is about 2-16%.
But, should be noted that operation of the present invention is equally applicable to the wider composition of atomic percent as mentioned above, this wider composition is referred to as iron-neodymium-boron composition in the following description.
In general, in argon gas anhydrous and anaerobic basically, inertia or vacuum atmosphere, induction heating melting merges ingot and forms the permanent magnet that even melt composition promptly can be made into this composition.Preferably, melt composition is solidified rapidly then and is made non-crystalline material or micro crystal material, wherein crystallite dimension in its full-size less than 400nm.Most preferably the material that solidifies rapidly be amorphous or under the superfine crystallite situation, crystallite dimension is less than about 20nm.For example utilize common fast melt-quenching operation to can be made into this material.According to routine, be fast melt-quenching iron-neodymium-boron band grind into powder then of amorphous or crystallite basically, also can directly use band certainly by the present invention.
Iron-neodymium-the boron particles that this moment is magnetic isotropy is then at enough pressure be hot pressed into complete dense material in the time.By convention, in mould, said composition is heated to suitable temperature and between the punch die composition compacting made basically closely knit flattened cylindrical material bodies fully up and down.In general crystallite dimension is reached complete densification less than the fast melt-quenching material of about 20nm in heating about 1 minute and hot pressing under such high temperature, the hot pressing body that obtains is permanent magnet.And this magnet is magnetic anisotropy (mean this magnet and have the preferred direction of magnetization) slightly.If bulk material is kept reasonable time under hot pressing temperature, crystallite dimension will reach about 20-500nm, preferred 20-100nm.
If the hot working again of hot pressing body, i.e. plastic deformation at high temperature, as allow crystal grain be out of shape, then products obtained therefrom demonstrates appreciable magnetic anisotropy.The hot working step is also equally at high temperature carried out in bigger mould usually, wherein the hot pressing body is carried out the punch die jumping-up and promptly makes the cylinder material body.Gained cylinder material physique ground is hard and intensity is high, it is characterized in that the about usually 7.5g/cm of its density
3, this is the complete basically fine and close density of magnetic alloy.
If suitably implement, high temperature process can form the sheet-like crystallite microscopic structure, and crystallite dimension is increased to about more than the 500nm.Before excessive grain is grown up and lost coercive force, be careful material is cooled off.The preferred magnetization direction of hot working product is parallel with pressing direction and vertical with the plastic flow direction usually.The hot working product is not uncommon according to the magnetic energy product that the jumping-up rate reaches about 222752.3AT/m (28 mega gaussorersted) yet.
Unmagnetized and the magnetic anisotropy of hot worked punch die jumping-up body, its coercive force is considerable.By the punch die jumping-up, make crystal grain in the base substrate flat and be oriented in the large scale direction vertical with pressing direction.The full-size of crystal grain is preferably about 100-300nm usually less than 500nm.These crystal grain comprise tetragonal crystal, iron wherein, and neodymium and boron ratio meet formula Nd
2Fe
14B.
The actual temperature that is used for hot pressing and these base substrates of hot working can change and will discuss in more detail in subsequent embodiment.In general, hot pressing is finished under identical high temperature with the hot working program, and this always must not accomplish certainly.
Although above-mentioned procedure of processing is generally routine operation, requiring needs two additional steps could make the anisotropic basically permanent magnet of hot pressing by the present invention at least.At first, with conventional breaking method such as mechanical milling method, comminuting method or hydrogen decrepitation method dwindle into hot worked anisotropic body granular, thereby make a certain amount of magnetic anisotropy particle.This technology does not change crystallite dimension or grain shape, as previously mentioned, grain shape be sheet and length less than about 500nm, be preferably about 100-300nm.These particles are hot pressed into anisotropic permanent magnet then, it is characterized in that magnetic energy product is 119331.5AT/m (15MGOe) at least, and in pressing process and do not require the operation of any magnetic aligning, and do not require in addition particle is carried out hot working.
Anisotropic particle can carry out hot pressing at the described identical heat-press step of isotropism particle by the front.In case of necessity, also quantitative fast melt-quenching isotropism particle can be mixed with anisotropic particle, so that the magnetic of advantageous embodiment gained magnet, because in composition, exist the isotropism particle can slightly reduce the magnetic property of hot pressing body.The isotropism particle can directly obtain by fast melt-quenching technology or in the annealing of isotropism particle and/or after being ground into powder.
The result has obtained the permanent magnet of anisotropic high energy product basically, its magnetic energy product is lower than the magnetic energy product of hot worked anisotropy magnet, but be higher than the bonding or the magnetic energy product of hot pressing isotropic magnet far away, and wherein in compacting or other hot procedure, need not any magnetic field orientating.More particularly, the isotropic magnet magnetic energy product of bonding is generally about 63643.5-79554.4AT/m (about 8-10MGOe), and the magnetic energy product of hot pressing isotropic magnet is generally about 79554.4-111376.2AT/m (about 10-14MGOe).In addition, the anisotropy magnet magnetic energy product of bonding is generally about 111376.2-143197.9AT/m (about 14-19MGOe).Fully with the permanent magnet of the present invention of anisotropic particle moulding be characterised in that magnetic energy product be at least 159108.8AT/m (20MGOe) and more than.
The magnetic property of the hot pressing anisotropy permanent magnet that forms by the present invention is with traditional B-H loop magnetic strength instrument (HGM) test determination.The sample placement location should make the axle that is parallel to direction of orientation be parallel to the direction in magnetic field that HGM adds, and degaussing then then reaches capacity each part sample magnetization.
The second quadrant demagnetization curve of the preferred anisotropic hot pressing permanent magnet of the present invention is shown in Fig. 1 and 2 (4 π M of kilogauss are to the coercive force (H) of kilo-oersted).Fig. 1 shows the magnetic property of the anisotropy permanent magnet that only forms with anisotropic particle by the preferred embodiment of the invention.Fig. 2 shows along each magnetic property of magnet shown in Figure 1.
Below be described in more detail concrete test piece.
Comparative example 1
For comparing, make common hot pressing isotropism permanent magnet and test.The nominal that is used to form this permanent magnetism and other given the test agent form by weight percentage for about 30.5% rare earth (this composition be neodymium at least about 95%, and all the other are essentially praseodymium), about 1.0% boron, about 2.5% cobalt, all the other are iron.Under excessive chilling condition, make the magnetic isotropy fast melt-quenching band of this composition with above-mentioned fast melt-quenching technology.
Make the hot pressing isotropic magnet then.At first, make preform, under about 750-800 ℃ temperature and about 77.22-92.67MPa (about 5-6 ton/square inch) pressure, this preform is hot pressed into the about 14mm of diameter then, the magnet of high about 15.5mm and heavily about 18g with above-mentioned band.
The magnetic property mean value that obtains with these magnets is the about 111376.2AT/m of magnetic energy product (BHmax) (14.0MGOe), about 0.8T of remanent magnetism (Br) (8.0 kilogauss (kG)) and HCJ (Hci) about 14.88 * 10
5A/m (18.7 kilo-oersteds (kOe)).
The magnetic alloy that is same as comparative example 1 with composition forms second magnet.But according to operation of the present invention, this magnetic composition is anisotropic powder.These anisotropic particles with a certain amount of band hot pressing of making by comparative example 1 after hot working obtain.Hot pressing and hot working step are carried out under about 750-800 ℃.The magnetic energy product of hot working anisotropy magnet is about 278440.4AT/m (35MGOe).
Adopt conventional hydrogen explosion/desorption method to obtain anisotropic powder then.Hydrogen explosion step is carried out with about 1/3 atmospheric hydrogen (about 33.33Pa (250 milli torr)) down at about 450 ℃, and desorption procedure is carried out under about 650 ℃.Under about 730 ℃ of temperature and about 77.22MPa (5 tons/square inch) pressure, a certain amount of anisotropy powder is hot pressed into the hot pressing anisotropy permanent magnet that size roughly is same as comparative example 1 hot-pressed magnets afterwards.In heat-press step, need not can reach following high energy product by magnetic field orientating.
The demagnetization curve of this hot pressing anisotropy magnet is shown in Fig. 1.With this magnet gained magnetic property mean value is the about 1670644AT/m of magnetic energy product (21.0MGOe), about 0.98T of remanent magnetism (9.8kG) and the about 827320A/m of HCJ (10.4kOe).
Compare with the hot pressing isotropic magnet of comparative example 1, remanent magnetism and magnetic energy product are all obviously improved, and coercive force has reduced.Although very the most important in some application facet at coercive force, for many other purposes, unique requirement is as long as coercive force is enough, just needs high remanent magnetism and high energy product.Those of ordinary skill in the present technique field as can be seen, the coercive force of the hot pressing anisotropy magnet of this embodiment is enough for these purposes, especially is like this when considering high energy product of the present invention and high remanent magnetism in the lump.
Fig. 2 shows from making and the magnetic property of the rectangle sample that performance hot pressing anisotropy magnet as shown in Figure 1 downcuts by embodiment 2 is described.Sample size is 9.4 * 9.4 * 7.6mm.Estimate on embodiment 2 pressing directions and the magnetic property on two normal axis directions vertical with this sample with pressing direction.
Positive according to expectation like that, the magnetic property that obtains on pressing direction is same as the magnetic property of the hot pressing anisotropy magnet of the embodiment 2 shown in the curve of aforementioned being designated as " HP " basically.Magnetic property mean value in vertical direction is the about 55688.1AT/m of magnetic energy product (7.0MGOe), and about 0.61T of remanent magnetism (6.1kG) and the about 922780A/m of HCJ (11.6kOe) are shown curve " X " and " Y " respectively.
From these data as can be seen, the anisotropy degree of above-mentioned sample can be determined by following anisotropic ratio formula:
Br/ ((Br)
2+ (Br
x)
2+ (Br
y)
2)
0.5Wherein Br is the remanent magnetism on the pressing direction, Br
xBe the remanent magnetism on the first direction vertical with pressing direction, and Br
yFor vertical with pressing direction and perpendicular to the remanent magnetism on the second direction of first horizontal direction.According to this formula, found that the anisotropy ratio of this sample is 0.77, show that the hot pressing anisotropy magnet has roughly 77% anisotropy degree.
Embodiment 3
In order to determine that whether hot pressing temperature is influential to the permanent magnet magnetic performance that the present invention forms, and is used to make other magnet with aforementioned magnetic alloy of giving an example.These magnets with anisotropic powder by embodiment 2 described method moulding, be last heat-press step at about 680 ℃, carry out under 750 ℃ or 790 ℃ of temperature.This result of the test is listed in the following table.
| Hot pressing temperature (℃) | Br T(kG) | Hci A／m(kOe) | BHmax AT／m(MGOe) |
| 680 750 790 | 1．02(10．2) 1．02(10．2) 1．02(10．2) | 819，365(10．3) 827，320(10．4) 803，455(10．1) | 182，975．1(23．0) 182，975．1(23．0) 182，975．1(23．0) |
From above data as can be seen, the magnetic property of hot pressing anisotropy magnet of the present invention is essentially identical under the hot pressing temperature between about 680-790 ℃.To all temperature, these performances are all basic identical.Therefore, very clear high energy product of the present invention is because of due to the magnetic anisotropy of particle, rather than mainly due to the hot compression parameters that is used for forming magnet, this just in time with prior art in opposite at explanation with the hot-pressed magnets of isotropism grain forming.Thus, it is very wide to make hot pressing anisotropy magnet of the present invention meet the requirements of the hot pressing temperature scope of magnetic property, this so that make magnet of the present invention create possibility on a large scale.
In order to determine whether to be subjected to the influence in the preorientation magnetic field that is provided with before the hot pressing, make other magnet with aforementioned same composition by the permanent magnet magnetic performance that the present invention forms.As described in embodiment 3, these magnets are made by embodiment 2 described methods, just restrain the column preform that the anisotropy powder are made the about 13.7mm of diameter and are about 8mm with 9.Earlier be about 11.93 * 10 in magnetic field intensity
5In the magnetic field of A/m (15kOe) the anisotropic powder orientation is made preform.This lubricated back of orientation preform is in about 730 ℃ of temperature and about 77.22MPa pressure (5 tons/square inch) hot pressing down.
The remanent magnetism of this magnet is about 1.04T (10.4kG) according to surveying and determination, and stupid remanent magnetism 1.02T (10.2kG) comparability of the hot pressing anisotropy magnet of this and embodiment 3 shows that magnetic field orientating can't obviously improve the magnetic property of hot pressing anisotropy magnet of the present invention.Therefore, the invention has the advantages that need not add magnetic field in the anisotropic particle course of processing can realize substantially, this explanation with prior art is also just in time opposite, adopts magnetic field orientating can improve the magnetic energy product of the bonded permanent magnet made from anisotropic particle greatly in the prior art.
Embodiment 5
Equally, make other magnet with forming the magnetic alloy that is same as comparative example 1.Contain the isotropism powder that adds in addition in the anisotropy powder in these magnets, magnet manufactured according to the present invention by roughly 75,50 and the 25Wt% anisotropic particle form.As previously mentioned, will be processed into anisotropic particle, afterwards the gained particle will be broken into anisotropic powder through the hydrogen decrepitation method by a certain amount of band hot pressing after heat that comparative example 1 is made.
By above-mentioned percentage by weight the anisotropy powder is mixed with fast melt-quenching isotropism band then.Under about 730 ℃ of temperature and about 77.22MPa (5 tons/square inch) pressure, the gained mixture is hot pressed into the hot pressing permanent magnet that size is similar to the magnet size of comparative example 1 afterwards.
The magnetic property mean value that obtains with these hot-pressed magnets is summarized as follows.
| Anisotropic powder (%) | Br T(kG) | Hci A／m(kOe) | BHmax AT／m(MGOe) |
| 75 50 25 | 0．95(9．5) 0．88(8．8) 0．85(8．5) | 875，050(11．0) 1，089，835(13．7) 1，233，025(15．5) | 147，175．8(18．5) 133，651．4(16．8) 120，922．7(15．2) |
As the sample of embodiment 2, the coercivity value shown in makes the high remanent magnetism of these samples and many application that high energy product is suitable for requiring to use permanent magnet very much here.
From as can be seen above-mentioned, be higher than the hot pressing isotropism permanent magnet magnetic energy product of making by prior art with the hot pressing permanent magnet magnetic energy product that the neodymium-iron that adds or do not add the isotropism particle-anisotropic particle of boron composition is made.Embodiment 2 and 3 magnet are only made with anisotropic particle, and anisotropic particle is in these embodiments made with the hot working anisotropy magnet of the about 278440.4AT/m of magnetic energy product (35MGOe), and the hot working anisotropy magnet has the potentiality that make the approaching about 397772AT/m (50MGOe) of magnetic energy product certainly.Therefore, can expect that the hot pressing anisotropic particle of making by the inventive method can reach the magnetic energy product of about 198886AT/m (25MGOe)-238663.2AT/m (30MGOe).And, can expect that these results and used hot pressing temperature have little or nothing to do with.
Although preferred composition must contain iron, neodymium and/or praseodymium and boron, the existence of cobalt is chosen wantonly.This composition also can contain other minor constituent such as tungsten, chromium, and nickel, aluminium, copper, magnesium, manganese, gallium, niobium, vanadium, molybdenum, titanium, tantalum, zirconium, carbon, tin, calcium, silicon, oxygen and nitrogen, condition is that isotropism contains the RE mutually that is magnetic with anisotropic particle
2TM
14B also has at least one to be rich in the additional phase of rare earth at the crystal boundary place simultaneously.Basic magnetic mutually in, TM is at least 60 atom % iron and RE at least 60 atom % neodymium and/or praseodymiums preferably preferably.
The more favourable feature of the present invention is need not any magnetic field orientating in hot pressing, and to obtain the required conventional hot working step of high energy product before need not carrying out, promptly can be made into high energy product anisotropy hot pressing permanent magnet, in fact unwanted these the two kinds of technologies of the present invention can make the magnet processed complexization of these types irrelevantly and limit the shape of gained magnet.These all are particularly advantageous characteristics of the present invention.Embodiment 2 that makes by the preferred embodiment of the invention and 3 sample show that a certain amount of anisotropic particle of hot pressing itself can obtain the composition of anisotropic magnetic basically that magnetic property is better than the isotropic magnet of existing bonding and hot pressing or the anisotropy magnet magnetic property that bonds.
The sample of embodiment 5 shows, the mixture of isotropism and anisotropic particle can be made into through hot pressing that its magnetic property also is better than boning and the magnetic composition of the existing isotropic magnet of hot pressing.
And the more favourable final geometry of permanent magnet that is characterised in that of the present invention is determined by hot press operation.Therefore, the obtainable shape quantity of anisotropic basically permanent magnet of the present invention is more than the obtainable shape quantity of existing hot working anisotropy magnet.And the shape kind that the hot pressing permanent magnet can be made into is far away more than the shape kind that can be made into the hot working anisotropy magnet, and wherein heat processing technique has limited obtainable shape kind.
Therefore, although the present invention is described its preferred embodiment, those skilled in the art can take other execution mode obviously.For example, magnetic-particle is formed and can be changed in preferred weight and atomic ratio scope, wherein can add or not add above-mentioned other composition, or adopt different or other procedure of processing production isotropism and anisotropic particle.Thus, the scope of the invention should be limited by the described scope of claims.
Patent application of the present invention requires the U.S. Patent application No.979 of preference, and 030 reaches the disclosure described in the wherein appended specification digest is incorporated in this for this paper reference.
Claims (14)
1. hot-pressed iron compact-rare-earth metal permanent magnet manufacture method, the step of this method comprises:
Make sheet anisotropy iron-rare earth metal particle, wherein anisotropy iron-rare earth metal particle forms with a kind of composition, and comprise 40 to 90% the iron or the mixture of cobalt and iron, 10 to 40% rare earth and at least 0.5% boron in atomic percent in the said composition;
A certain amount of anisotropy iron of hot pressing-rare earth metal particle, wherein under the state of no alignment magnetic field, carry out this step, thereby make anisotropy iron-rare earth metal particle basically can magnetic aligning in heat-press step, this heat-press step forms hot pressing anisotropy iron-rare-earth metal permanent magnet, this hot-pressed iron compact-rare-earth metal permanent magnet contains flaky crystalline grain and demonstrates magnetic anisotropy, its magnetic energy product is higher than the magnetic energy product of the hot pressing isotropic magnet with substantially similar composition, but is lower than the magnetic energy product of the hot working anisotropy magnet with substantially similar composition;
Magnetic energy product at least 15 mega gaussorersteds of this hot pressing anisotropy iron-rare-earth metal permanent magnet wherein.
2. hot-pressed iron compact according to claim 1-rare-earth metal permanent magnet manufacture method, wherein anisotropy iron-rare earth metal particle adopts and comprises 26 to 32% rare earth by weight percentage, 0.7 the boron to 1.1%, all the other are essentially the composition of iron and make.
3. hot-pressed iron compact according to claim 2-rare-earth metal permanent magnet manufacture method, wherein said composition also comprises 2 to 16% cobalt.
4. hot-pressed iron compact according to claim 1-rare-earth metal permanent magnet manufacture method, wherein the crystallite dimension of anisotropy iron-rare earth metal particle is not more than 500mm.
5. hot-pressed iron compact according to claim 1-rare-earth metal permanent magnet manufacture method wherein mixes isotropism iron-rare earth metal particle before the hot pressing and forms mixture with anisotropy iron-rare earth metal particle.
6. hot-pressed iron compact according to claim 5-rare-earth metal permanent magnet manufacture method, wherein isotropism iron-rare earth metal particle adopts and comprises 26 to 32% rare earth by weight percentage, 0.7 the boron to 1.1%, all the other are essentially the composition of iron and make.
7. hot-pressed iron compact according to claim 6-rare-earth metal permanent magnet manufacture method, wherein said composition also comprises 2 to 16% cobalt.
8. hot-pressed iron compact according to claim 1-rare-earth metal permanent magnet manufacture method, wherein anisotropy iron-rare earth metal particle is made according to the method that may further comprise the steps:
Make a certain amount of isotropism iron-rare earth metal particle;
Should be hot pressed into isotropic magnet by quantitative isotropism iron-rare earth metal particle;
Isotropic magnet hot working is made the crystal grain plastic deformation of isotropism iron-rare earth metal particle, thereby form anisotropy magnet; And
This anisotropy magnet fragmentation is made anisotropy iron-rare earth metal particle with this anisotropy magnet.
9. hot-pressed iron compact according to claim 8-rare-earth metal permanent magnet manufacture method, wherein broken step comprises hydrogen explosion desorption technique.
10. hot-pressed iron compact-rare-earth metal permanent magnet manufacture method, wherein comprise 26 to 32% rare earth by weight percentage in this permanent magnet, at least 90% of this component is a neodymium, this permanent magnet also comprises 0.7 to 1.1% boron, and all the other are essentially iron, and the step of this method comprises: hot-pressed iron compact-rare earth metal composition fast melt-quenching was formed cold belt shape material;
Make isotropism iron-rare earth metal particle with this strip material;
This isotropism iron-rare earth metal particle is hot pressed into isotropic magnet;
This isotropic magnet hot working is made the iron-rare earth metal particle generation plastic deformation of this isotropic magnet, thereby make anisotropy magnet;
This anisotropy magnet fragmentation is made sheet anisotropy iron-rare earth metal particle with this anisotropy magnet; And
A certain amount of anisotropy iron of hot pressing-rare earth metal particle, wherein under the state of no alignment magnetic field, carry out this step, thereby make anisotropy iron-rare earth metal particle basically can magnetic aligning in heat-press step, this heat-press step forms hot-pressed iron compact-rare-earth metal permanent magnet;
Thereby make iron-rare-earth metal permanent magnet demonstrate the magnetic energy product of at least 15 mega gaussorersteds.
11. hot-pressed iron compact according to claim 10-rare-earth metal permanent magnet manufacture method, wherein broken step comprises hydrogen explosion technology.
12. hot-pressed iron compact according to claim 10-rare-earth metal permanent magnet manufacture method, wherein the crystallite dimension of anisotropy iron-rare earth metal particle is not more than 500nm.
13. hot-pressed iron compact according to claim 10-rare-earth metal permanent magnet manufacture method, wherein hot-pressed iron compact-rare-earth metal permanent magnet comprises that also one or more are selected from tungsten, chromium, nickel, aluminium, copper, magnesium, manganese, gallium, niobium, vanadium, molybdenum, titanium, tantalum, zirconium, carbon, tin, calcium, silicon, the additive of oxygen and nitrogen.
14. hot-pressed iron compact according to claim 10-rare-earth metal permanent magnet manufacture method, wherein this permanent magnet also comprises 2 to 16% cobalt.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/979,030 US5352301A (en) | 1992-11-20 | 1992-11-20 | Hot pressed magnets formed from anisotropic powders |
| US979,030 | 1992-11-20 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1089386A CN1089386A (en) | 1994-07-13 |
| CN1061162C true CN1061162C (en) | 2001-01-24 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN93120694A Expired - Fee Related CN1061162C (en) | 1992-11-20 | 1993-11-20 | Hot-pressed magnets formed from anisotropic powders |
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| Country | Link |
|---|---|
| US (1) | US5352301A (en) |
| EP (1) | EP0599365A1 (en) |
| JP (1) | JPH07307211A (en) |
| CN (1) | CN1061162C (en) |
| CA (1) | CA2098553A1 (en) |
| SG (1) | SG46630A1 (en) |
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| US7857773B2 (en) * | 2003-12-30 | 2010-12-28 | Medicis Technologies Corporation | Apparatus and methods for the destruction of adipose tissue |
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| US6998538B1 (en) * | 2004-07-30 | 2006-02-14 | Ulectra Corporation | Integrated power and data insulated electrical cable having a metallic outer jacket |
| US7208684B2 (en) * | 2004-07-30 | 2007-04-24 | Ulectra Corporation | Insulated, high voltage power cable for use with low power signal conductors in conduit |
| US20060122509A1 (en) * | 2004-11-24 | 2006-06-08 | Liposonix, Inc. | System and methods for destroying adipose tissue |
| US8142200B2 (en) | 2007-03-26 | 2012-03-27 | Liposonix, Inc. | Slip ring spacer and method for its use |
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| US9272332B2 (en) * | 2011-09-29 | 2016-03-01 | GM Global Technology Operations LLC | Near net shape manufacturing of rare earth permanent magnets |
| CN103123862B (en) * | 2011-11-21 | 2015-09-09 | 中国科学院宁波材料技术与工程研究所 | Improve the method for hot pressing/thermal deformation radially oriented Nd-Fe-B permanent magnetic ring performance and axial uniformity thereof |
| CN103123843B (en) * | 2011-11-21 | 2015-10-07 | 中国科学院宁波材料技术与工程研究所 | A kind of preparation method of fine grain anisotropy densification Nd-Fe-B permanent magnet |
| JP6471594B2 (en) * | 2015-04-10 | 2019-02-20 | 住友電気工業株式会社 | Rare earth magnet material and method for producing rare earth magnet material |
| CN105161240A (en) * | 2015-10-13 | 2015-12-16 | 南通长江电器实业有限公司 | High-performance rare earth permanent magnet material |
| CN105632749B (en) * | 2015-12-29 | 2017-12-05 | 江苏大学 | A kind of preparation method of high-performance anisotropy Nanocomposite magnet |
| US10851446B2 (en) | 2016-03-31 | 2020-12-01 | Iowa State University Research Foundation, Inc. | Solid state grain alignment of permanent magnets in near-final shape |
| JP6666228B2 (en) * | 2016-09-30 | 2020-03-13 | ミネベアミツミ株式会社 | Manufacturing method of rare earth iron-based permanent magnet |
| EP3625807B1 (en) * | 2017-05-19 | 2021-03-24 | Robert Bosch GmbH | Hot deformed magnet, and a method for preparing said hot deformed magnet |
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- 1993-06-16 CA CA002098553A patent/CA2098553A1/en not_active Abandoned
- 1993-10-30 SG SG1996006867A patent/SG46630A1/en unknown
- 1993-10-30 EP EP93203052A patent/EP0599365A1/en not_active Withdrawn
- 1993-11-19 JP JP5312854A patent/JPH07307211A/en active Pending
- 1993-11-20 CN CN93120694A patent/CN1061162C/en not_active Expired - Fee Related
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| CN1065152A (en) * | 1991-02-01 | 1992-10-07 | 三菱材料株式会社 | Terres rares-iron-cobalt-B anisotropic magnet |
Also Published As
| Publication number | Publication date |
|---|---|
| US5352301A (en) | 1994-10-04 |
| CA2098553A1 (en) | 1994-05-21 |
| SG46630A1 (en) | 1998-02-20 |
| EP0599365A1 (en) | 1994-06-01 |
| JPH07307211A (en) | 1995-11-21 |
| CN1089386A (en) | 1994-07-13 |
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